Embodiments of the present invention relate in general to instruction sequencing in an out-of-order (OoO) processor, and more specifically to allocating and deallocating reorder queue entries for an OoO processor.
In an out-of-order (OoO) processor, an instruction sequencing unit (ISU) dispatches instructions to various issue queues, renames registers in support of OoO execution, issues instructions from the various issue queues to the execution pipelines, completes execution instructions, and handles exception conditions. Register renaming is typically performed by mapper logic in the ISU before the instructions are placed in their respective issue queues.